Flowing drink, by the sound of it, where Magna Carta was signed (9)
I believe the answer is:
runnymede
'where magna carta was signed' is the definition.
(I've seen this before)
'flowing drink by' is the wordplay.
'flowing' becomes 'runny' (synonyms).
'drink by' becomes 'mede' (I can't justify this - if you can you should believe this answer much more).
'runny'+'mede'='RUNNYMEDE'
'the sound of it' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for runnymede that I've seen before include "Where King John signed Magna Carta in 1215" , "Place in Surrey" , "Place where Magna Carta was signed" , "Democratic convention site" , "Site of signing Magna Carta" .)